The present invention relates to a solar cell module. More particularly, the present invention relates to a support for an array of photoelectric solar cells which simplifies the method of assembling solar cell arrays into a module and permits the mechanical connection of modules to each other and for mounting on supporting standards at the proper angle of inclination for interception of solar radiation.
A solar cell array comprises a plurality of individual cells and interconnector means for electrically connecting adjacent cells in a matrix. Typically, the individual solar cells are arranged in columns and rows and the interconnector means are positioned so as to connect the cells in the requisite series and/or parallel circuit arrangement. The circuit arrangement, of course, depends upon the desired voltage and short circuit current.
Generally, for terrestrial applications, a solar cell array is fabricated and sold as a module comprising the solar cell array mounted on an electrically nonconductive support member having terminals provided therein. The module also has a top cover over the solar cell array. This cover is a transparent protective coating which protects the solar cells against environmental hazards and also serves to maintain the cells in proper position. The module typically is fitted into a metal frame which provides the mechanical strength for the array and the module to protect them against damage due to environmental loadings, such as from wind, snow, ice, rain, etc. The metal frame also serves as a means for mounting the module at the proper angle to receive insolation.
The standard method of forming the cells into an array of the type described begins with the step of aligning the cells in rows and columns. This is done on an alignment or spacing jig. Relatively flexible metallic interconnectors are attached to the cell electrodes by soldering or welding. Each interconnector extends from the top electrode of one cell to the bottom electrode of the next adjacent cell, and rows of cells are similarly connected. Consequently, there is a lot of handling and movement of individual cells in order to properly index or position the cells and complete the soldering and welding. After the electrical series and/or parallel cell matrix has been formed, it is necessary to mount the cell matrix on a rigid support. Thus, the cell matrix is lifted from the jig and placed on the substrate for support. Typically the matrix is then soldered via metallic interconnectors to terminal posts provided on the support.
Finally, a protective cover is placed over the cells. This must be done while taking particular care to keep the cells from touching each other; otherwise cells touching will result in short circuiting the system.
As will be appreciated, in its normal operational environment, a solar cell module is generally exposed to extreme temperature changes or thermal cycling. This thermal cycling causes thermal expansion and contraction of the cells, the supporting substrate and the cover material. Since all these materials have vastly different thermal coefficients of expansion, there is a relative movement of the cells toward and away from one another. Existing solar cell modules employ flexible electrical interconnectors to accommodate this relative movement; however, extreme care must be taken in mounting the solar cell array between its substrate and cover so that relative movement of the cells does not cause adjacent cells to contact each other and short circuit.
As indicated hereinabove, in the past these solar cell modules have been further supported in a metal frame so as to provide the high mechanical strength required for mounting the modules in the field for actual use where they are subjected to the environmental loadings such as wind, snow, ice or rain, etc.
Although various types of supports have been proposed on which to mount solar cell arrays, the supports suggested in the past do not simultaneously possess the important qualities of rigidity and light weight; nor do they provide a simple means for positioning and maintaining solar cell arrays in the desired location. Other deficiencies, too, are known.